you will obtain a return of about 190% APR !!!!
Anyone planning to have this lucrative APR offer must have known what can happen after you purchased the account. It is very possible that the original owner can claim the account anytime just with a signed message from the bitcoin address they used prior to selling the account. It's very risky IMO but it's up to you. Just read this before you decide. I appreciate OP linking the post but a quote would be a better presentation IMO.
It isn't forbidden to sell an account but anyone buying it is opening themselves to getting scammed. All the seller has to do is say that the account was hacked and request it to be handed back to them in a Bitcoin signed message from an address they previously deposited from.